Conventionally, as one of the molding methods for sealing a semiconductor element with resin to form a semiconductor device, a transfer molding method is used. For the transfer molding method, a resin-sealing apparatus using a resin-sealing mold composed of an upper die and a lower die is used. According to this molding method, a lead frame of a semiconductor element is clamped with the upper die and the lower die, and resin is melted in a pot and fed to a cavity of the mold under pressure to be cured. After that, the upper die or the lower die is moved in a vertical direction to open the mold, whereby a semiconductor device that is a molded product is taken out.
As one example of the semiconductor device, there is a surface-mounting type light-emitting device in which a lens is formed with a resin package sealing a semiconductor light-emitting element. FIG. 7 shows an example of a surface-mounting type light-emitting diode. FIG. 7(a) is a plan view, and FIG. 7(b) is a side view.
In a light-emitting diode 61, semiconductor light-emitting elements 64 mounted on lead frames 62, 63 are covered with a translucent resin package 65. In the resin package 65, there are provided a lens part 68 condensing light output from the semiconductor elements 64, and a leg part 69 covering the lead frames 62, 62 and the semiconductor light-emitting elements 64 in an integrated manner. An outer circumference of the lens part 68 is provided with a curved surface 66. Since the curved surface 66 is present, a reduced-diameter part 67 is formed in a connecting portion between the lens part 68 and the leg part 69.
Thus, by providing the reduced-diameter part 67 to be a concave part in a side surface of the light-emitting diode 61, light output sideways from the semiconductor light-emitting elements 64 can be reflected totally from the curved surface 66 without waste, and can be condensed in a main light extraction direction F, so that the brightness can be enhanced.
However, in the case of molding the resin package 65 as shown in FIG. 7, due to the presence of the reduced-diameter part 67, the resin-sealing mold composed of the upper die and the lower die cannot be opened, so that a product cannot be molded.
Herein, Patent Document 1 proposes, as the resin-sealing mold, a resin-sealing apparatus provided with a middle die in addition to the upper die and the lower die. In this resin-sealing apparatus, the middle die is provided between the upper die and the lower die, a cavity is filled with resin from a pot via the middle die to seal the cavity with the resin, the lower die is lowered first, and then, the middle die is separated from the upper die to open the mold, whereby a molded product is taken out.
Although the resin-sealing apparatus described in Patent Document 1 has the middle die, the middle die merely plays a role as a gate for filling the cavity with resin. Therefore, even when an attempt is made to mold the resin package 65 with the reduced-diameter part 67 as shown in FIG. 7, the mold cannot be opened.
Patent Document 1: JP 2003-11187 A